Dampening units for applying treatment and/or application liquids to treatment surfaces in order to produce extensive, uniform, and generally very thin coatings from the respective application liquid are. Such dampening units are used, for example, in printing devices or printing machines for offset printing. In such machines, dampening unit is assigned to each of the printing cylinders to produce a color set of a multicolor print.
In one known printing device of this type, the dampening unit has a horizontally arranged brush that can be driven to rotate. The brush is provided with the application liquid and bears against an outer surface of the printing cylinder to transfer the liquid as the brush rotates about its brush axis.
Also known is a printing device comprising a plate cylinder or printing cylinder on which a multicolor printed image is produced via a plurality of color application rollers. Provided upstream of the color application rollers, in relation to the direction of rotation of the printing cylinder, is a horizontally arranged dampening unit for applying an application liquid to the printing cylinder. The dampening unit comprises a plurality of rollers that are driven to rotate. One of these rollers is an application roller that bears against the printing roller. A brush or brush roller that is driven to rotate applies the application liquid by spraying a layer on a further roller, which then transfers the application liquid to the application roller.